Choosing and modifying components
16 min
- Match cryoprecipitate, plasma, or another component to the factors that need replacing
- Select plasma without donor antibodies against the recipient's red cells
- Choose leukoreduction, irradiation, or washing for the risk each one reduces
- Check a red-cell request against the hemoglobin threshold for the patient's setting
Try first
Get the idea
Match the component to the deficit
Each component replaces something specific:1
| Component | Replaces | Laboratory finding it answers |
|---|---|---|
| Red cells | Oxygen-carrying capacity | Hemoglobin below the threshold for the setting |
| Platelets | Platelets | A low count with bleeding, or below a prophylaxis threshold |
| Plasma | The coagulation factors together | Raised INR and APTT with bleeding |
| Cryoprecipitate | Fibrinogen, factor VIII, factor XIII, von Willebrand factor | Low fibrinogen with bleeding |
Cryoprecipitate is used mainly to replace fibrinogen. Factor concentrates are preferred for hemophilia A, von Willebrand disease and factor XIII deficiency. An INR of 1.7 or less reflects enough factor activity for hemostasis, and plasma given to correct it is a relative contraindication.1
Plasma compatibility runs the other way
Plasma carries the donor's anti-A and anti-B. It must be ABO-compatible with the recipient's red cells. Group AB plasma has neither antibody and suits a recipient of any group. Group O plasma has both and suits only group O recipients. The D type of plasma does not matter.1
One modification for each risk
- Leukoreduction removes most donor leukocytes. It reduces febrile reactions, HLA alloimmunization and cytomegalovirus transmission.
- Irradiation stops donor T lymphocytes from dividing and prevents transfusion-associated graft-versus-host disease. The T lymphocytes that leukoreduction leaves behind are still viable, so leukoreduction cannot stand in for irradiation.
- Washing removes plasma proteins. It serves recurrent severe allergic reactions and IgA-deficient patients with anti-IgA.
Irradiation indications include intrauterine transfusion, cellular components from blood relatives, HLA-selected components, hematopoietic progenitor cell transplant recipients and purine analogue therapy such as fludarabine.1
Thresholds follow the setting
For most stable hospitalized adults, the 2023 AABB guideline recommends considering red cells when hemoglobin is below 7 g/dL.2 After acute myocardial infarction, a 2025 AABB guideline suggests a liberal strategy, with transfusion below 10 g/dL.3 The transfusion service reviews each request against the patient's setting, and the treating clinician makes the transfusion decision.4
References
- Association for the Advancement of Blood & Biotherapies, American Red Cross, America's Blood Centers, Armed Services Blood Program. Circular of Information for the Use of Human Blood and Blood Components. June 2024. Accessed September 27, 2026.
- Carson JL, Stanworth SJ, Guyatt G, et al. Red blood cell transfusion: 2023 AABB international guidelines. JAMA. 2023;330(19):1892-1902. doi:10.1001/jama.2023.12914
- Pagano MB, Stanworth SJ, Dennis J, et al. Red cell transfusion in acute myocardial infarction: AABB international clinical practice guidelines. Ann Intern Med. 2025;178(10):1469-1477. doi:10.7326/ANNALS-25-00706
- Bloch EM, Campbell-Lee S, McKenna DH Jr, Montemayor-Garcia C, Schwartz J, Shaz B, Storry J, eds. Technical Manual. 22nd ed. AABB; 2026.
Watch one
Tomás Rivera, 58, MRN 6627405, is group B, D-negative. He needs 4 units of plasma before a procedure. The freezer holds group O, A, B and AB plasma, some from D-positive donors.
Which plasma can he receive?
- Start from his red cells. Group B cells carry the B antigen.
Plasma compatibility is decided by the donor's antibodies meeting the recipient's red cells.
- Set aside group O plasma. Its anti-B would bind his red cells.
Group O plasma carries both anti-A and anti-B.
- Set aside group A plasma for the same reason.
Group A plasma carries anti-B.
- Keep group B plasma, which has anti-A only, and group AB plasma, which has neither antibody.
Neither group B nor group AB plasma carries anti-B.
- Accept any D type.
D compatibility is unnecessary for plasma.
Your turn
Use it
- Henryk Nowak, 71, MRN 3981046, is admitted with an acute myocardial infarction.
- He has chronic lymphocytic leukemia treated with fludarabine. His transfusion record requires irradiated cellular components.
- His hemoglobin is 8.6 g/dL, and his cardiologist orders 1 red-cell unit.
- The audit software flags the order because the hemoglobin is above 7 g/dL.
- The group A units on the shelf are leukoreduced, and none is irradiated.
The clue that settled this case is the patient's setting. Acute myocardial infarction made 8.6 g/dL a supported trigger, fludarabine made irradiation a requirement, and an isolated low fibrinogen called for cryoprecipitate.
Results
- Match cryoprecipitate, plasma, or another component to the factors that need replacing
- Select plasma without donor antibodies against the recipient's red cells
- Choose leukoreduction, irradiation, or washing for the risk each one reduces
- Check a red-cell request against the hemoglobin threshold for the patient's setting
To review
6 questions from this step will come back in Review.
Keep
Sources checked
The rest of this step
A short briefing, a demonstration at the bench, 3 practice problems and a short case.
A free account opens the rest and keeps your progress.